Health Consultation

Drinking and Irrigation Water Quality
Blue Ridge Elementary School
Lakeside, Navajo County, Arizona

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
Public Health Service
Agency for Toxic Substances and Disease Registry
Division of Health Assessment and Consultation
Atlanta, Georgia 30333

Purpose
This health consultation evaluates results of irrigation well samples collected by the Arizona
Department of Environmental Quality in October 2003. Previous results obtained by the Blue
Ridge Elementary School District in the summer of 2003 indicated trichloroethylene (TCE)
levels above the U.S. Environmental Protection Agency’s (EPA) Maximum Contaminant Level
(MCL). In addition, the most recent (2002) Annual Water Quality Report from the drinking
water supplier, Arizona Water Company, was reviewed.
Background and Statement of Issues
A previous health consultation (Blue Ridge Elementary School, Lakeside, Navajo County,
Arizona Health Consultation-April 30, 2003) reviewed environmental conditions at Blue Ridge
Elementary School. Parents and school staff were concerned that environmental exposures were
causing students to be absent from school. Drinking water quality reports, indoor air quality data,
food safety, environmental sanitation records, student attendance rates, and the results of an
annual parent satisfaction survey were evaluated in the consultation. Arizona Department of
Health Services (ADHS) concluded that environmental conditions at Blue Ridge Elementary
School posed no apparent public health hazard, and that attendance rates were similar to
statewide attendance rates.
As part of the 2003 health consultation, ADHS requested that the school district conduct water
sampling from the on-site irrigation water wells for the school grounds. Those sampling results
were not available when the 2003 health consultation was completed.
The school was built in 1974 and is located at 1200 West White Mountain Boulevard in
Lakeside, Arizona. Lakeside is on State Highway 260, southeast of Show Low in southern
Navajo County. The Blue Ridge Elementary School has 700 students enrolled in kindergarten
through 3rd grade, and employs 75 teachers and support staff (1).
Drinking Water Quality
The Arizona Water Company provides drinking water to Blue Ridge Elementary School from
wells located throughout the Lakeside area. Our April 2003 health consultation reviewed the
water company’s annual reports from 1997 through 2001. Industrial solvents or gasoline
components were not detected in the Lakeside drinking water, and levels of naturally occurring
elements (such as aluminum, calcium, iron, and magnesium) were below levels of concern.
These facts suggested that the drinking water at the school did not represent a health threat.
A review of the 2002 annual report indicated that drinking water supplied to Blue Ridge
Elementary School continues to meet all state and federal safe drinking water standards (2).
Irrigation Water Quality
The Blue Ridge Elementary School grounds are flood-irrigated with groundwater from a water
storage tank that collects groundwater from the two on-site wells. At the time of the April 2003
health consultation, current water quality data for the irrigation well water was not available. The
school maintenance supervisor reported that past sampling results from the wells had been
acceptable. The school district obtained a composite water sample in the summer of 2003 from
the water storage tank at the request of the Arizona Department of Health Services. The sample

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results exceeded the Maximum Contaminant Level (MCL) of 5 parts per billion (ppb) for TCE in
drinking water. This sample was taken from the water storage tank and included water from both
on-site irrigation wells.
The Arizona Department of Environmental Quality (ADEQ) collected additional groundwater
samples in October 2003. The samples collected by ADEQ from the two irrigation wells and two
storage tanks were analyzed by the Arizona State Laboratory for volatile organic compounds
(VOCs). TCE was the only contaminant detected (Table 1) in these samples.
While results confirmed the presence of TCE in groundwater, the source is not known and is
being investigated by ADEQ. School officials were informed of sample results and this consult has
been prepared to document our assessment process.
Table 1: Irrigation Water Sampling Results
TCE (trichloroethylene)
concentration
(micrograms per liter, µg/l)
5.3
2.3
2.5
2.5

Sample Location
Irrigation Well #1
Irrigation Well #2
Irrigation Water Storage Tank (Sample #1)
Irrigation Water Storage Tank (Sample #2)

Above MCL?
(5 µg/l)
Yes
No
No
No

Discussion
Irrigation Well #1 is only used for on-site irrigation. The school maintenance supervisor stated
that the school grounds are irrigated when it does not interfere with student use during the school
day. During summer months, some irrigation does occur during daytime hours. The maintenance
department avoids irrigating when it will leave the fields wet for scheduled events. The
frequency and amount of irrigation needed during the school year and the winter months is
limited because the average snowfall for Pinetop-Lakeside is 47.2 inches per year (4).
Limited dermal, inhalation, and ingestion exposures are possible for anyone who contacts the
contaminated irrigation water (Table 2).
Table 2. Completed Exposure Pathways
Source
Irrigation
Well #1

EXPOSURE PATHWAY ELEMENTS
Point of
Route of
Estimated
Media
Exposure
Exposure
Population
Groundwater

Inhalation
Dermal
Ingestion

Irrigation
water

700

Contaminant
of Concern
TCE

Exposures were calculated for children, as they are the most sensitive population. We estimated
exposures to irrigation water containing trichloroethylene by assuming that children play in the

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flood irrigation water for one hour, 24 times per year (once per week for 6 months) for 12 years.
We assumed that a child would incidentally ingest 0.05 liters (50 milliliters) during each play
event, and used a child body weight of 15 kilograms (5).
Our estimated exposure dose is based on the maximum concentration detected and represents a
“worst case scenario.” The ingested dose from drinking water was doubled in order to take into
account skin absorption and inhalation of vapors resulting from contact with the irrigation water.
The assumption is that the combined dose from these two routes of exposure is equivalent to that
of ingestion (6). Childhood doses were compared to the chronic ATSDR Minimal Risk Level for
chronic ingestion of trichloroethylene, which is an exposure dose below which no adverse, noncancer health effects are expected.
Table 3. Well #1. Trichloroethylene (TCE) Non-Cancer Estimates
TCE
concentration
(mg/L)
5.3
5.3
5.3

1

Pathway
Inhalation
Dermal
Ingestion

Child’s Estimated
Non-cancer Daily Dose
(mg/kg-day)
0.12
0.001
0.0461

Health
Guideline
(mg/kg -day)
Not available
Not available
0.20

Exceeds
Guideline?
--No

Source
-

--

MRL2

The exposure dose calculated for ingestion (0.023 mg/kg-day) was doubled to take into account exposures from
inhalation and dermal contact.
2
MRL: Health-based comparison values have been developed by ATSDR for chemical in various environmental
media. The values define the concentration at or below which carcinogenic and/or noncarcinogenic health effects are
not likely to occur after exposure. Contaminant concentrations exceeding these values do not necessarily pose a
health threat, but have been further evaluated to determine the potential for health effects.

Trichloroethylene (TCE)
Trichloroethylene is a man-made chemical originally developed as an anesthetic for surgery. It is
used today as an industrial cleaner to remove grease from metal parts. It is also used in many
consumer products, including typewriter correction fluid, paint removers, paint strippers,
adhesives/glues, spot removers and cleaning fluids for rugs. At room temperature, TCE is a
colorless liquid. It has an odor similar to ether or chloroform, and evaporates very quickly.
Health effects from exposure to TCE vary depending on the amount to which a person is exposed
and how long the exposure lasts. Dizziness, headaches, slowed reaction times, sleepiness, and
facial numbness have occurred in workers breathing TCE or in people who use products
containing TCE in poorly ventilated areas. Concentrations causing these effects are higher than
the allowable occupational exposure level of 50 parts per million. Irritation of the eyes, nose, and
throat also occur under these conditions. More severe effects on the central nervous system, such
as unconsciousness and possible death, can occur from drinking or breathing higher levels of
TCE. The effects caused by exposures to TCE disappear when the exposure ends. Levels of TCE
in the normal environment are generally well below levels of those found in the workplace.
Studies in animals show that ingesting or breathing levels of TCE that are higher than typical
environmental levels can produce nervous system changes, liver and kidney damage, effects on
the blood, tumors of the liver, kidney, lung, and male sex organs, and possible cancer of the
tissues that form the white blood cells. Results of a few studies in some pregnant animals
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exposed to TCE in air or food showed effects in unborn animals or in newborns. None of these
effects have been definitely shown to occur in humans.
The U.S. Environmental Protection Agency is currently reevaluating the carcinogenic
classification for TCE. The International Agency for Research on Cancer (IARC) has determined
that TCE is a probable human carcinogen based on limited human data and sufficient data in
experimental animals. (3)
Child Health Issues
All exposure dose estimates were calculated assuming childhood exposure, thus incorporating
exposure assumptions that reflect a child’s greater intake of water relative to body weight. All
conclusions and recommendations about using water from these wells were based on the
characteristics of this sensitive population.
Conclusions
Based the levels of TCE found in water samples from Irrigation Well #1 and the exposure
scenarios used in our assessment, the use of Irrigation Well #1 for watering the school grounds
poses no public health hazard.
The TCE levels found in the irrigation wells pose no apparent health hazard to children who play
in, or come into contact with, the irrigation water.
Groundwater samples from irrigation well #1 contained TCE levels slightly above the Maximum
Contaminant Level for drinking water. Water from this well is used solely for flood irrigation of
the school grounds and is not a source of drinking water. The source of the TCE is unknown and is
currently being investigated by ADEQ.
Based on a review of the most recent (2002) Annual Water Quality Report from the Arizona
Water Company, drinking water supplied to the school meets all federal and state standards.
Recommendations
The Arizona Department of Health Services will review the 2003 Annual Water Quality Report
from the Arizona Water Company when it becomes available.
Public Health Action Plan
The Arizona Department of Health Services has worked with the Blue Ridge School District to
address public health-related concerns and provided an interim update on sample results until
this consultation could be completed.
This health consultation will be distributed to the ADEQ Water Quality Assurance and
Revolving Fund Program. It will also be sent to the Blue Ridge Elementary School District.

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References
1. Arizona Department of Health Services. Blue Ridge Elementary School, Lakeside, Navajo
County, Arizona Health Consultation. April 2003.
2. Arizona Water Company. 2002. 2002 Annual water quality report for Lakeside, Arizona
PWSID #09-003--.
3. Case Studies in Environmental Medicine. ATSDR. January 2001. U.S. Department of Health
and Human Services, Agency for Toxic Substances and Disease Registry, Division of Health
Education and Promotion).
4. Arizona Department of Commerce. Phoenix, AZ 9/2003) http:www.azcommerce.com.
5. U.S. Environmental Protection Agency (U.S. Environmental Protection Agency). 2002. Childspecific exposure factors handbook. National Center for Environmental Assessment, Washington
D.C.; EPA 600/p/00/002B. National Information Service, Springfield, VA:PB2003-101678.
6. Washington State Department of Health. Health Consultation. Cadet Manufacturing.
Vancouver, Clark County, Washington. January 2002.

PREPARERS OF REPORT
Kristina Schaller
Don Herrington
Arizona Department of Health Services
Office of Environmental Health

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CERTIFICATION
The Arizona Department of Health Services, under a cooperative agreement with the Agency for
Toxic Substances and Disease Registry (ATSDR), prepared this health consultation on drinking
and irrigation water at Blue Ridge Elementary School, Lakeside, Navajo County, Arizona. It was
prepared in accordance with approved methodology and procedures existing at the time.

____________________________________
Allen Robison
Technical Project Officer
Superfund and Program Assessment Branch
Division of Health Assessment and Consultation

The Division of Health Assessment and Consultation has reviewed this health consultation and
concurs with its findings.

_________________________________
Bobbi Erlwein
Team Leader, Cooperative Agreement Team
Superfund and Program Assessment Branch
Division of Health Assessment and Consultation
ATSDR

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